First time an adversary ties Bugs to the railroad tracks instead of the other way round.
Bugs uses a prop to simulate a disaster for Crusher (here, a broken bone) and then shows up as someone who can help (a doctor)... but doesn't, really. This gag would be repeated a few years later in Bunny Hugged, with a slightly different angle.
The locomotive number on the train bearing down on Bugs near the end of this short is "1043", which is the same as the film's official production number, seen on the first title card.
First appearance of Crusher and second time Bugs takes on an adversary that's bigger than he is.